arch/x86/kernel/dumpstack_32.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   4  */
   5 #include <linux/kallsyms.h>
   6 #include <linux/kprobes.h>
   7 #include <linux/uaccess.h>
   8 #include <linux/hardirq.h>
   9 #include <linux/kdebug.h>
  10 #include <linux/export.h>
  11 #include <linux/ptrace.h>
  12 #include <linux/kexec.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/bug.h>
  15 #include <linux/nmi.h>
  16
  17 #include <asm/stacktrace.h>
  18
  19 static void *is_irq_stack(void *p, void *irq)
  20 {
  21         if (p < irq || p >= (irq + THREAD_SIZE))
  22                 return NULL;
  23         return irq + THREAD_SIZE;
  24 }
  25
  26
  27 static void *is_hardirq_stack(unsigned long *stack, int cpu)
  28 {
  29         void *irq = per_cpu(hardirq_stack, cpu);
  30
  31         return is_irq_stack(stack, irq);
  32 }
  33
  34 static void *is_softirq_stack(unsigned long *stack, int cpu)
  35 {
  36         void *irq = per_cpu(softirq_stack, cpu);
  37
  38         return is_irq_stack(stack, irq);
  39 }
  40
  41 void dump_trace(struct task_struct *task, struct pt_regs *regs,
  42                 unsigned long *stack, unsigned long bp,
  43                 const struct stacktrace_ops *ops, void *data)
  44 {
  45         const unsigned cpu = get_cpu();
  46         int graph = 0;
  47         u32 *prev_esp;
  48
  49         if (!task)
  50                 task = current;
  51
  52         if (!stack) {
  53                 unsigned long dummy;
  54
  55                 stack = &dummy;
  56                 if (task != current)
  57                         stack = (unsigned long *)task->thread.sp;
  58         }
  59
  60         if (!bp)
  61                 bp = stack_frame(task, regs);
  62
  63         for (;;) {
  64                 void *end_stack;
  65
  66                 end_stack = is_hardirq_stack(stack, cpu);
  67                 if (!end_stack)
  68                         end_stack = is_softirq_stack(stack, cpu);
  69
  70                 bp = ops->walk_stack(task, stack, bp, ops, data,
  71                                      end_stack, &graph);
  72
  73                 /* Stop if not on irq stack */
  74                 if (!end_stack)
  75                         break;
  76
  77                 /* The previous esp is saved on the bottom of the stack */
  78                 prev_esp = (u32 *)(end_stack - THREAD_SIZE);
  79                 stack = (unsigned long *)*prev_esp;
  80                 if (!stack)
  81                         break;
  82
  83                 if (ops->stack(data, "IRQ") < 0)
  84                         break;
  85                 touch_nmi_watchdog();
  86         }
  87         put_cpu();
  88 }
  89 EXPORT_SYMBOL(dump_trace);
  90
  91 void
  92 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
  93                    unsigned long *sp, unsigned long bp, char *log_lvl)
  94 {
  95         unsigned long *stack;
  96         int i;
  97
  98         if (sp == NULL) {
  99                 if (regs)
 100                         sp = (unsigned long *)regs->sp;
 101                 else if (task)
 102                         sp = (unsigned long *)task->thread.sp;
 103                 else
 104                         sp = (unsigned long *)&sp;
 105         }
 106
 107         stack = sp;
 108         for (i = 0; i < kstack_depth_to_print; i++) {
 109                 if (kstack_end(stack))
 110                         break;
 111                 if ((i % STACKSLOTS_PER_LINE) == 0) {
 112                         if (i != 0)
 113                                 pr_cont("\n");
 114                         printk("%s %08lx", log_lvl, *stack++);
 115                 } else
 116                         pr_cont(" %08lx", *stack++);
 117                 touch_nmi_watchdog();
 118         }
 119         pr_cont("\n");
 120         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 121 }
 122
 123
 124 void show_regs(struct pt_regs *regs)
 125 {
 126         int i;
 127
 128         show_regs_print_info(KERN_EMERG);
 129         __show_regs(regs, !user_mode(regs));
 130
 131         /*
 132          * When in-kernel, we also print out the stack and code at the
 133          * time of the fault..
 134          */
 135         if (!user_mode(regs)) {
 136                 unsigned int code_prologue = code_bytes * 43 / 64;
 137                 unsigned int code_len = code_bytes;
 138                 unsigned char c;
 139                 u8 *ip;
 140
 141                 pr_emerg("Stack:\n");
 142                 show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
 143
 144                 pr_emerg("Code:");
 145
 146                 ip = (u8 *)regs->ip - code_prologue;
 147                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 148                         /* try starting at IP */
 149                         ip = (u8 *)regs->ip;
 150                         code_len = code_len - code_prologue + 1;
 151                 }
 152                 for (i = 0; i < code_len; i++, ip++) {
 153                         if (ip < (u8 *)PAGE_OFFSET ||
 154                                         probe_kernel_address(ip, c)) {
 155                                 pr_cont("  Bad EIP value.");
 156                                 break;
 157                         }
 158                         if (ip == (u8 *)regs->ip)
 159                                 pr_cont(" <%02x>", c);
 160                         else
 161                                 pr_cont(" %02x", c);
 162                 }
 163         }
 164         pr_cont("\n");
 165 }
 166
 167 int is_valid_bugaddr(unsigned long ip)
 168 {
 169         unsigned short ud2;
 170
 171         if (ip < PAGE_OFFSET)
 172                 return 0;
 173         if (probe_kernel_address((unsigned short *)ip, ud2))
 174                 return 0;
 175
 176         return ud2 == 0x0b0f;
 177 }